(2S)-2-acetamido-5-oxopentanoate (2S)-2-acetamido-5-oxo-pentanoate (2S)-2-acetamido-5-keto-valerate 2-Acetamido-5-oxopentanoate N-Acetyl-L-glutamate 5-semialdehyde 2-acetamido-5-oxovalerate CHEBI:29123 2-acetamido-5-oxo-pentanoate